From patchwork Sat May 10 15:41:45 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Bj=C3=B8rn_Mork?= X-Patchwork-Id: 347699 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 7B5EB14008A for ; Sun, 11 May 2014 01:42:54 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756467AbaEJPmv (ORCPT ); Sat, 10 May 2014 11:42:51 -0400 Received: from canardo.mork.no ([148.122.252.1]:43755 "EHLO canardo.mork.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751820AbaEJPmU (ORCPT ); Sat, 10 May 2014 11:42:20 -0400 Received: from nemi.mork.no (nemi.mork.no [IPv6:2001:4641:0:2:e8b:fdff:fe08:971]) (authenticated bits=0) by canardo.mork.no (8.14.4/8.14.4) with ESMTP id s4AFgBdo026582 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NOT); Sat, 10 May 2014 17:42:11 +0200 Received: from bjorn by nemi.mork.no with local (Exim 4.80) (envelope-from ) id 1Wj9Pf-0000Jr-BE; Sat, 10 May 2014 17:42:11 +0200 From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= To: Cc: , Alexey Orishko , Oliver Neukum , Enrico Mioso , David Laight , =?UTF-8?q?Bj=C3=B8rn=20Mork?= Subject: [PATCH net-next 07/11] net: cdc_ncm: set reasonable padding limits Date: Sat, 10 May 2014 17:41:45 +0200 Message-Id: <1399736509-1159-8-git-send-email-bjorn@mork.no> X-Mailer: git-send-email 2.0.0.rc2 In-Reply-To: <1399736509-1159-1-git-send-email-bjorn@mork.no> References: <1399736509-1159-1-git-send-email-bjorn@mork.no> MIME-Version: 1.0 X-Virus-Scanned: clamav-milter 0.98.1 at canardo X-Virus-Status: Clean Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org We pad frames larger than X to maximum size for devices which don't need a ZLP after maximum sized frames. This allows the device to optimize its transfers for one fixed buffer size. X was arbitrarily set at 512 bytes regardless of real buffer maximum, causing extreme overheads due to excessive padding of larger tx buffers. Limit the padding to at most 3 full USB packets, still allowing the overhead to payload ratio of 3/1. Signed-off-by: Bjørn Mork --- drivers/net/usb/cdc_ncm.c | 8 ++++++-- include/linux/usb/cdc_ncm.h | 1 + 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c index faa494c0377e..e28b530bff3a 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -201,6 +201,10 @@ static void cdc_ncm_update_rxtx_max(struct usbnet *dev, u32 new_rx, u32 new_tx) /* max qlen depend on hard_mtu and rx_urb_size */ usbnet_update_max_qlen(dev); + + /* never pad more than 3 full USB packets per transfer */ + ctx->min_tx_pkt = clamp_t(u16, ctx->tx_max - 3 * usb_maxpacket(dev->udev, dev->out, 1), + CDC_NCM_MIN_TX_PKT, ctx->tx_max); } /* helpers for NCM and MBIM differences */ @@ -936,7 +940,7 @@ cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign) /* variables will be reset at next call */ } - /* If collected data size is less or equal CDC_NCM_MIN_TX_PKT + /* If collected data size is less or equal ctx->min_tx_pkt * bytes, we send buffers as it is. If we get more data, it * would be more efficient for USB HS mobile device with DMA * engine to receive a full size NTB, than canceling DMA @@ -946,7 +950,7 @@ cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign) * a ZLP after full sized NTBs. */ if (!(dev->driver_info->flags & FLAG_SEND_ZLP) && - skb_out->len > CDC_NCM_MIN_TX_PKT) + skb_out->len > ctx->min_tx_pkt) memset(skb_put(skb_out, ctx->tx_max - skb_out->len), 0, ctx->tx_max - skb_out->len); else if ((skb_out->len % dev->maxpacket) == 0) diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h index bbc4ce9ffef5..0aac70ee23b6 100644 --- a/include/linux/usb/cdc_ncm.h +++ b/include/linux/usb/cdc_ncm.h @@ -115,6 +115,7 @@ struct cdc_ncm_ctx { u16 tx_seq; u16 rx_seq; u16 connected; + u16 min_tx_pkt; }; u8 cdc_ncm_select_altsetting(struct usbnet *dev, struct usb_interface *intf);